An ill wind

What's the meaning of the phrase 'An ill wind'?

A misfortune.

What's the origin of the phrase 'An ill wind'?

The use of 'ill wind' is most commonly in the phrase 'it's an ill wind that blows nobody any good'. This is first recorded in John Heywood's A dialogue conteinyng the nomber in effect of all the prouerbes in the Englishe tongue, 1546:

"As you be muche the worse. and I cast awaie.
An yll wynde, that blowth no man to good, men saie.
Wel (quoth he) euery wind blowth not down the corn
I hope (I saie) good hap [luck] be not all out worn."

Heywood's meaning was that a wind that was unlucky for one person would bring good fortune to another. This sailing metaphor has frequently been invoked to explain good luck arising from the source of others' misfortune, and it probably pre-dates 1546.

That meaning, which is still understood today, was subverted somewhat later to provide a second meaning. In Rob Roy, Sir Walter Scott included:

"Nane were keener against it than the Glasgow folk, wi' their rabblings and their risings, and their mobs, as they ca' them now-a-days. But it's an ill wind blaws naebody gude."

The meaning there is clearly the opposite of the old proverb, that is, a wind that didn't provide benefit to someone would be a bad and unusual one indeed.

Into the 20th century we find a punning joke on the phrase that has been attributed to many people, notably Sir Thomas Beecham, although I'm unable to authenticate the true source. This calls the notoriously difficult-to-play French horn "the wind that nobody blows good".

This little joke was popularized by Danny Kaye's character in the 1947 film The Secret Life of Walter Mitty, although in that version they unfairly opted for the tuneful though also difficult oboe:

And the oboe it is clearly understood
Is an ill wind that no one blows good.